As is known to those skilled in the art of stringed musical instruments, the strings of the instrument extend between two critical contact points, typically provided on or at the nut of the instrument and on or at the bridge of the instrument. Typically, each of the strings also extends beyond at least one of the critical contact points where it is secured to a tuning peg or tuning machine provided on the instrument for adjusting the tension of the string. Similarly, the other end of the string is typically anchored at a point beyond the other critical contact point. On the other hand, in some stringed musical instruments, the ends of the strings are secured at or closely adjacent to one of the critical contact points.
As is also known in the art, the sounds produced by the strings may be affected by the harmonic and pitch tuning of the individual strings. The harmonic or string length tuning of the strings is commonly adjusted by altering the distance between the critical contact points at which the string contacts the bridge and nut elements of the instrument. The pitch or fine tuning of the strings is a result of the tension in the strings which is generally adjusted by rotation of the tuning pegs or machines that pull on a string to increase tension. In some instances, fine tuning adjustment screws or devices are provided for adjusting the string tension. Generally, each of the strings of a musical instrument are both pitch and harmonically tuned individually and independently of the other strings of the musical instrument.
Tremolo or vibrato devices for stringed musical instruments are also widely known. They are typically used to simultaneously and significantly either reduce or increase the tension on all strings of the musical instrument, thereby producing unusual tone variations or vibrato. Examples of tremolos are shown in U.S. Pat. No. 2,741,146 to Fender and U.S. Pat. Nos. 4,171,661, 4,497,236 and 4,967,631 to Floyd Rose, the inventor herein.
As described in the '236 patent, a typical tremolo device includes a base plate having a flange depending from and attached to the bottom thereof. The base plate has knife edges at the front corners or outer front sides that allow pivotal movement of the base plate about fulcrum supports mounted to the body of a guitar. More particularly, a base plate support mechanism, such as upstanding posts is provided on the guitar body and receives the knife edges on the base plate so that the base plate is pivotal about the upstanding posts. Further, a series of string attachment means are mounted on the base plate. In such a configuration, it is necessary that the strings be anchored at points in a plane above the level of the plane of the base plate in order to induce a torque about a fulcrum on the attachment points. A spring or plurality of springs in tension is attached at one end to the flange which extends below the base plate, and at the other end to a wall, often indirectly by way of a hook that is directly attached to the wall, of an elongated cavity necessarily carved below the surface of the guitar body, providing an opposing torque to counterbalance the torque produced by the strings when they are in tune, such that the tremolo device remains static until a tremolo arm attached to the base plate is forced in an up or down direction.
Such a configuration requires that the guitar be permanently modified by the user by carving out a large recess through the guitar to allow for the flange to fit therein and by carving out the elongated cavity surrounding each counterbalancing spring. Furthermore, GIBSON-style guitars, some of the most commonly used guitars in the industry, are notoriously difficult to retrofit with a fulcrum tremolo device to replace a tune-o-matic and stop-tail piece style bridge. For example, they require routing in order to provide the tuning stability provided by double-locking and fine tuning with a fulcrum about which to pivot, such as in the '661, '236, and '631 patents. Some manufacturers such as BIGSBY, MAESTRO, SCHALLER, KAHLER and STETSBAR have produced tremolos to retrofit to GIBSON-style guitars, but they are known to have reduced string travel and hence little pitch variance and also lose their pitch tuning upon return of the tremolo arm to its normal, rest position.
Tremolo devices created for attachment to a GIBSON guitar without modification and that purportedly return the guitar to its original pitch are described in U.S. Pat. Nos. 5,392,680 and 7,544,873 to Stets. These tremolo devices each offer a low-profile design in which a tremolo arm is attached to a pinion gear that meshes with a gear rack fixed to a moveable plate that rides on ball bearings. The moveable plate in each of such tremolo devices moves forward and backward. Each movement of the plate causes the attached springs to be in tension and hence pull the plate back to the original position upon release of the tremolo arm, whether it is raised or lowered.
Although such a tremolo apparatus has a low profile and is installed with little or no modification, the interface of the ball bearings on the moveable plate introduces unwanted sliding friction in the system. Additionally, the patents to Stets do not incorporate fine tuners nor double-locking in which each string is locked at the nut and at the bridge assembly. Consequently, they induce friction from sliding strings over the nut. For this reason, balancing of the guitar strings and opposing springs about a fulcrum in tandem with a double-locking feature is the best known solution for reducing friction in a tremolo.
Another device, previously produced by SCHALLER ELECTRONIC GmbH, for Floyd Rose, utilizes a set of springs in parallel attached at one end to a location on a base plate between a fulcrum of the device, formed by indentations on posts inserted into a mounting frame, and the body of the guitar. The other end of the device is attached to a string mounting assembly that is caused to move by a corresponding movement of a tremolo arm. In this manner, the springs provide a force to balance the force of the strings and maintain the device in a rest position until a force is applied to the tremolo arm to move the base plate. Although the device is known to use as many as ten (10) springs, the springs do not provide enough tension to counterbalance the force of the commonly used string sets.
It is also known in the prior art that the tremolo arm of a guitar is a straight or slightly curved shaft attached to a tremolo device through various mechanisms. One configuration for a tremolo arm, produced by SCHALLER ELECTRONIC GmbH, has a nut having a central axis oriented perpendicularly to the guitar body, slid onto the shaft of the tremolo arm. The tremolo arm is inserted into a bushing and the nut is subsequently threaded onto a threaded portion of the bushing. Such a configuration requires routing the instrument below the base plate in order for the arm to rotate in an downward or upward direction, i.e., toward or away from the guitar. Such a design also allows the tremolo arm to subtly rock in relation to the nut and bushing. In other words, this design has inherent but unwanted clearances to ensure the components fit together. In an alternative arrangement, the tremolo arm is threaded or snapped onto a mounting stud fixed to a base plate of the tremolo, such as those made by STETSBAR. In both arrangements, a number of components are necessary to attach the tremolo arm. In the case of the SCHALLER-type designs, the portion of the tremolo arm that is inserted into the bushing must be long enough to accommodate all of these components. This increased length requires routing in the body to provide clearance for the tremolo arm and is thus undesirable.
The present invention addresses at least certain of the shortcomings of the prior art. In particular, according to one aspect of the present invention, there is provided a low-profile tremolo. According to a further aspect of the present invention, there is provided a fine tuning, double-locking tremolo apparatus applying a fulcrum balance. In accordance with a still further aspect of the present invention, a tremolo apparatus is provided which includes an associated tremolo arm with a side mounted tension adjustment and attachment screw. As such, the present invention constitutes a further step toward an optimum tremolo and tuning apparatus for stringed musical instruments.